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college math help please

How do you solve the equation all four equations are 1 problem. i have to solve for w, x, y and z

x + y + z - w= 4

2x + y - z + w =3

x - 5y + 2z +w = -4
-x -y + z + 3w = 2

 
Anonymous

Asked by Anonymous at 11:33 PM on Sep. 13, 2010 in

This question is closed.
Answers (7)
  • Ecodani is right on. Another method to use is linear algebra by building a matrix.


    http://answers.yahoo.com/question/index?qid=20100418015604AAYNtxS


    Write your equations this way, and solve for the diagonal (underlined).
    1   1   1  -1   4
    2   1  -1   1   3
    1  -5   2   1  -4
    -1 -1   1   3   2


    Add/subtract rows from each other till the only values >0 left are those on the diagonal (x,y,z,w) and last column (value).


    My solution: x=-7, y=14, z=21 2/3 and w=24 2/3 

    anng.atlanta

    Answer by anng.atlanta at 12:58 AM on Sep. 14, 2010

  • First solve for x. Plug that equation in for x in the following equation. Then solve that equation for y. Plug the x and y in the 3rd equation andnsolve for w. Finally, you only have z as your variable. Solve for z.

    ecodani

    Answer by ecodani at 11:48 PM on Sep. 13, 2010

  • i swear i should know that because it was only 2 semesters ago that i was doing that problem.. sorry =( i'll try to figure it out & get back to you IF i remember! =P
    rAbella

    Answer by rAbella at 11:47 PM on Sep. 13, 2010

  • I SHOULD know this, lol, Good Luck! I'm drawing a blank!
    sstepph

    Answer by sstepph at 7:00 AM on Sep. 14, 2010

  • best way to make sure you are getting help is to visit the professer and ask them. Many will help during office hours and others know of the best tutors available many times for free.
    steveiguana

    Answer by steveiguana at 7:23 AM on Sep. 14, 2010

  • I am no help, sorry. I can barely help my fifth grader with his math. :(
    KTMOM

    Answer by KTMOM at 8:34 AM on Sep. 14, 2010

  • OMG, so sorry-I never understood that kind of math!
    NicolesMommy

    Answer by NicolesMommy at 12:14 AM on Sep. 15, 2010